task modal: audio info panel for Get Lyrics (title/artist/length/lyrics)

Display-only panel at the top of the Get Lyrics run-task form (single file only):

- Backend: GET /file-browser/audio-meta?path= — ffprobe format tags + duration,
  plus a second probe for embedded lyrics (USLT/SYLT/lyrics* keys, case-insensitive).
  Returns { title, artist, duration, hasLyrics }; tolerant of missing tags/probe
  failures.
- Client: files.audioMeta(path) + AudioMeta type in useFilesAPI.
- TaskRunnerModal: prefetch audioMeta for get-lyrics single-file runs (bypasses
  the hasTrackPickers early-return, error-tolerant), and render AudioMetaPanel
  above TaskInputForm — title/artist + a muted length + Lyrics: Yes/No chip,
  filename fallback. Directories + other tasks unaffected (no panel, no probing).

Verified ffprobe logic on a real embedded-lyrics file. tsgo clean; formatted.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/api/file-browser/router.ts

@@ -454,6 +454,74 @@ router.get('/audio-tracks', async (ctx) => {
   return ctx.json(tracks);
 });
 
+// Read-only audio metadata for the Get Lyrics run-task panel: title/artist/duration + whether the file
+// already has embedded lyrics. Tolerant of missing tags / probe failures (defaults to empty/0/false).
+router.get('/audio-meta', async (ctx) => {
+  const user = ctx.get('user');
+  const rootDir = getRootDir(user, ctx.req.query('root') ?? undefined);
+  const relPath = (ctx.req.query('path') || '').replace(/^\/+/, '');
+  if (!relPath) throw errors.BAD_REQUEST('path is required');
+  const absPath = resolveUserPath(rootDir, relPath);
+
+  // Format tags + duration.
+  const fmtProc = Bun.spawn(
+    [
+      'ffprobe',
+      '-v',
+      'error',
+      '-show_entries',
+      'format=duration:format_tags=title,artist,album,TITLE,ARTIST',
+      '-of',
+      'json',
+      absPath,
+    ],
+    { stdout: 'pipe', stderr: 'ignore' },
+  );
+  const fmtOut = await new Response(fmtProc.stdout).text();
+  await fmtProc.exited;
+
+  let format: { duration?: string; tags?: Record<string, string> } = {};
+  try {
+    format = (JSON.parse(fmtOut) as { format?: typeof format }).format ?? {};
+  } catch {
+    format = {};
+  }
+  const tags: Record<string, string> = {};
+  for (const [k, val] of Object.entries(format.tags ?? {})) tags[k.toLowerCase()] = val; // ID3 case varies
+  const durNum = format.duration ? parseFloat(format.duration) : 0;
+
+  // ID3 lyrics frames (USLT/SYLT) don't reliably surface in format_tags — probe stream+format tags and
+  // flag lyrics if any key matches USLT/SYLT/lyrics (case-insensitive; some muxers emit `lyrics-XXX`).
+  const lyrProc = Bun.spawn(
+    ['ffprobe', '-v', 'error', '-show_entries', 'stream_tags:format_tags', '-of', 'json', absPath],
+    { stdout: 'pipe', stderr: 'ignore' },
+  );
+  const lyrOut = await new Response(lyrProc.stdout).text();
+  await lyrProc.exited;
+
+  let hasLyrics = false;
+  try {
+    const data = JSON.parse(lyrOut) as {
+      format?: { tags?: Record<string, string> };
+      streams?: Array<{ tags?: Record<string, string> }>;
+    };
+    const keys = [
+      ...Object.keys(data.format?.tags ?? {}),
+      ...(data.streams ?? []).flatMap((s) => Object.keys(s.tags ?? {})),
+    ];
+    hasLyrics = keys.some((k) => /uslt|sylt|lyrics/i.test(k));
+  } catch {
+    hasLyrics = false;
+  }
+
+  return ctx.json({
+    title: tags.title ?? '',
+    artist: tags.artist ?? '',
+    duration: Number.isFinite(durNum) ? durNum : 0,
+    hasLyrics,
+  });
+});
+
 // Recursively probe a folder's videos and group them by track layout, so the task runner can offer
 // one set of audio/subtitle pickers for a whole season when every episode matches — and flag the
 // odd files out when they don't. Two files "match" when their audio (language + channel count) and